1. Field of the Invention
The present invention relates to a stable silicone microemulsion composition obtained from a carboxy-modified organopolysiloxane using a silicone-based nonionic surfactant. This silicone microemulsion composition can be used in cosmetic materials and household products.
2. Description of the Prior Art
Examples of conventionally known silicone microemulsions include amino silicone microemulsions obtained from amino group-containing organopolysiloxanes using a nonionic surfactant and an organic acid. The average particle size within these microemulsions is 100 nm or less, which is extremely small compared with the average particle size of macroemulsions (which exceed 100 nm). These amino silicone microemulsions exhibit excellent emulsion stability, excellent shear stability when used in diluted form, and superior adsorption to substrates, and are therefore used within a wide range of industrial fields, as fiber treatment agents, release agents, water repellent agents and hair cosmetic materials and the like (Patent Document 1).
Techniques for obtaining microemulsions from organopolysiloxanes other than amino group-containing organopolysiloxanes are now being investigated. For example, a hair cosmetic material that exhibits superior adhesion to hair, comprising an organopolysiloxane having carboxyl groups within a portion of a dimethylpolysiloxane chain and a surfactant has been proposed (Patent Document 2). Further, the use of a microemulsion with an average particle size of not more than 150 nm, obtained from a carboxy-modified organopolysiloxane using a nonionic surfactant and/or an anionic surfactant, as the main agent within a fiber treatment agent has also been proposed (Patent Document 3). Moreover, a solubilized composition obtained by solubilizing a carboxy-modified organopolysiloxane with a branched polyoxyethylene alkyl ether-type nonionic surfactant has also been proposed (Patent Document 4).    Patent Document 1: JP 02-284959 A    Patent Document 2: JP 4,338,648 B    Patent Document 3: JP 63-270875 A    Patent Document 4: WO 2010/110047